Floppy EMU- suddenly mounting three images at once

iantm

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Sep 8, 2025
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I’m using a floppy EMU with my Mac SE. it has suddenly started mounting three copies to the desktop when you mount a virtual floppy.

It wasn’t doing this when I first got it. It started mounting two images at one point. Now it’s three.

I have a Maceffects performer installed so I’m going to pull it and see if somehow that’s affecting things. But anyone else using a floppy emu running into this issue? Even the creator of the device has never seen this before though.
IMG_6504.jpeg
IMG_6503.jpeg
 
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iantm

New Tinkerer
Sep 8, 2025
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Michigan
Small update: a different FDHD board and an 800k board don’t exhibit this behavior. It’s something unique to the one logic board I have where it points multiple copies at once.

Also: mounting 800k disks, only single image appears. So it might be something up with the signals being sent to the SWIM chip, interpreting it as three different types of disks? (HD, 400k, 800k)

I’ve tried two different floppy emus and even tried removing the 030 accelerator thinking that might be the problem.
Nope.
What could it possibly be about a logic board that is causing these floppy images to mount more than once?
The good news is that they’re functional- they just kind of get in the way like that.
 
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iantm

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Sep 8, 2025
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Michigan
Another small find:

I suppose there might be something wrong with my FDHD logic board… but there might be a way to force the Floppy EMU to stay in one emulation mode. It could be that the SWIM chip is responding to signals for all three types of disks (400k, 800k, 1.4MB) and somehow mounting all three at once.
 

JDW

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I have the Performer and WarpSE (prototype) and never had that behavior when using my FEMU on my SE. It seems you have more than one SE motherboard and different experiences with each. The ROM and SWIM (or IWM) are all socketed, so you may wish to try swapping out those chips to see if it has any positive impact on your motherboard which mounts 3 copies of the virtual disk on your FEMU.
 

iantm

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I wasn't aware you could pull out SWIM chips! I'll definitely try flipping the SWIM chips between the two boards to see if it makes any difference.
 
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JDW

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I wasn't aware you could pull out SWIM chips!

Both ROM chips and the SWIM (or IWM on the 800K drive version Motherboard) should be socketed like this...

1758674020541.png


If you have a mix of ROM versions and have a SWIM and IWM, just put a sticker on each chip and mark what is what before you start swapping. That's easier than looking up the part numbers. It won't hurt anything to use old ROMs with the newer SWIM, or newer ROMs with the older IWM. Your objective will be to see if the issue is a board level issue or chip level.
 

iantm

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Ah, ok! I wasn't sure if these were swappable between boards. I have two SWIM chips on 1988 SE boards and 800k WIM. I'm slightly worried I might brick a board but I'll make sure I get a proper IC puller.
 

JDW

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Ah, ok! I wasn't sure if these were swappable between boards. I have two SWIM chips on 1988 SE boards and 800k WIM. I'm slightly worried I might brick a board but I'll make sure I get a proper IC puller.
Or a small flathead screwdriver that you can use at each end of the chip to slowly and carefully wedge it out. Mixing the chips won't harm the board.
 
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